Introduction:
The increase in the number of childhood brain tumor survivors warrants
detailed research to increase our knowledge regarding the possible
physical and psychosocial adverse outcomes of tumor and tumor therapy.
The aim of this study was to evaluate the current bone health by
measuring the bone mineral density (BMD) in irradiated, adult long-term
survivors of childhood brain tumors.

Material and methods:
We studied a national cohort of 74 adult survivors of childhood brain
tumors treated with irradiation in Finland between 1970 and 2008. Dual
X-ray absorptiometry (DXA) was performed for the femoral necks, total
hips, and lumbar spine. Laboratory tests were conducted for evaluating
the pituitary, thyroid, and gonadal functions. The participants were
interviewed, examined clinically, and the disease and treatment related
data were retrieved from the patient files.

Results: One fourth of the patients (23.6%) had sex- and age-normalized z-scores below the expected range for age (z-score ≤ −2.0). Mean BMD scores were decreased in all the DXA measurement sites. Male sex was associated with low BMD (p < .05), while body mass index (BMI) had a significant positive association with BMD (p < .01).
Mode of irradiation (with or without spinal irradiation) or inclusion
of chemotherapy in the treatment did not affect BMD significantly.
However, patients with a ventriculoperitoneal shunt had lower BMD than
those without a shunt (p < .05). Follicle stimulating hormone (FSH) and luteinizing hormone (LH) were negatively associated with BMD in women (p < .05).
However, a higher cumulative dose of glucocorticoids during treatment
was not associated with lower BMD, while low BMD was significantly
associated with previous fractures in long bones.

Discussion:
Low BMD should be taken in consideration in treatment of irradiated
childhood brain tumor survivors especially in those with previous
fractures in long bones.